[glib/glib-2-58: 5/6] glocalfile: Use MAXSYMLINKS when following symlinks

[Ondrej Holy <oholy src gnome org>]

commit aa5b7206e0e23ca280a6bd016619399eb6d046cc
Author: Ondrej Holy <oholy redhat com>
Date:   Fri Sep 21 16:12:51 2018 +0200

    glocalfile: Use MAXSYMLINKS when following symlinks
    
    Currently, readlink() is used only 12 times when expanding symlinks.
    However, kernel uses 40 for this purpose and it is defined as MAXSYMLINKS.
    Use that constant if available, or 40. See:
    https://github.com/torvalds/linux/include/linux/namei.h.

 gio/glocalfile.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/gio/glocalfile.c b/gio/glocalfile.c
index a547bcda0..064755981 100644
--- a/gio/glocalfile.c
+++ b/gio/glocalfile.c
@@ -1610,7 +1610,15 @@ expand_symlinks (const char *path,
         }
 
       num_recursions++;
-      if (num_recursions > 12)
+
+#ifdef MAXSYMLINKS
+      if (num_recursions > MAXSYMLINKS)
+#else
+      /* 40 is used in kernel sources currently:
+       * https://github.com/torvalds/linux/include/linux/namei.h
+       */
+      if (num_recursions > 40)
+#endif
         {
           g_free (target);
           return NULL;